Airplane having a variable lifting surface



Oct. 30, 1934. J. GERIN AIRPLANE HAVING A VARIABLE LIFTING SURFACE 7 Sheets-Sheet 1 Filed Dec. 5. 1932 J Geri;

Oct. 30, 1934. GERlN 1,979,194

AIRPLANE HAVING A VARIABLE LIFTING SURFACE Filed Dec. 5, 1932 '7 Sheets-Sheet 2 t1: T o," s1 l -J O O 2\ Q9 0 B Oct. 30, 1934. .1. GERIN AIRPLANE HAVING A VARIABLE LIFTING SURFACE Filed Deb. s. 1932 7 Sheets-Sheet s AIRPLANE HAVING A VARIABLE LIFIING SURFACE Filed Deb. 5, 1932 7 Sheets-Sheet 4 Oct. 30, 1934. I

J. GERIN AIRPLANE HAVING A VARIABLE LIFTING SURFACE Filed Dec. 5, 1932 7 Sheets-Sheet 5 v rem 2 Oct. 30, 1934. J. GERIN AIRPLANE HAVING A VARIABLE LIFTING SURFACE Filed Dec. 5, 1952 7 Sheets-Sheet 6 Jywh pvvenrral? Oct. 30, 1934, J. GERIN AIRPLANE HAVING A VARIABLE LIFTING SURFACE Filed Dec. 5. 1932 7Sheets-Sheet '7 on. I 30,

ma'm a vanunm sonracn- Jacques Gel-in; lioulogne sunseine,

I Application December 5,4932, Serial No. 45,798 In France December 9, 1931 Claims. (c ane) This invention relates airplanesthe lifting. surface of which can vary by extending out,;

along a fixed lifting plane, a movable surface'constituted by transverse ribs connected by a fiexi- 5 ble covering. The wing having a reduced sur face is constituted by the fixed plane, and the wing having a large surface is constituted by the extended surface which bears on the fixed portion by increasing the width of the latter but by-- preserving the span of the latter;

The fixed portion of the wing is adapted to lift the airplane at high speeds; it has a-small lifting power and is of great fineness; the portion to be extended out, which is adapted to lift or supportthe airplane at low speeds and particularly for facilitating taking oif'and landing, must have a great curvature in order to have a very high lifting action. ,1 But, it will be understood that for winding 9 up, in the known manner, ribs ofgreat curvature on operating arranged within the fuselages or hulls, large spaces-must be available, this being an inconvenience,

For first remedying this inconvenience, the invention mainly consists in forming the ribs of the surfacestobe extendedout of elements pivoted on each other so that the structure constituted by these elements may assume, according as they bear or not on the fixed portion of th wing, a high curvature or no curvature.

The invention also concerns, by way of detail .objects forming a part of the main object, other advantageous features the most important of which are as follows:

5 (a) The ribs are constituted by at least two main elements: a first element which, by its front portionbears, when extendedout, on the fixed part of the wing, the rear'portion of which constitutes the portion of the rib, and a seci cud element which is pivoted on the front portion of the first element and'constitutes the leadingportion of the rib, the flexible covering of the 1mfoldable surface being provided only on leading and trailing portions of't he rib.

i (b) The ribs. can also'be constituted by three elements: a central element bearing on the fixed portion of the wing, a leading element, and a trailing element, the two latter being pivoted on thecentral element and being restored'by re- ,silient means so as to extend substantially according to one andthe same rectilinear axis when the rib is no longer in' contact with the 7 fixed portion of the (c), The leading and trailing portions ofthe i ribs have their pivot points on thecentral portion, such that they present an end bearing through one or more rollers on the fixed portion of the.

'(d) The leading portion of each rib, and eventually the trailing portion, are combined with -locking means resiliently restored in position and so arranged that, through amovable member bearing on the fixed portion of the wing when the movablesurface is extended out, the leading portion of the rib, and, eventually, the portion, arerigidly connected to the central portion (e) The trailing portion of each rib can be pivoted onthe central portion of the rib, and

without bearing on the fixed portion of the wing,

so as to be able, in antagonism with resilient returning means, to move with the speedof flight for causing the curvature of the wing having a large surface to vary.

(f) The fixed portion of the wing is preferably made of metal and is constituted by longitudinal casings through which pass cables connected to the ends of the movable surfaca for causing the tinge to extend out, as well as the warping con- (g) The warping ailerons provided on the fixed surfaces are arrangedat the ends of the latter and occupy the entire width of the same, so that the central portion of the end ribs of the movable surfaces may bear thereon forallowing to warp the end portions'of the movable surfaces when they are extended out. (h) The aileron at the end of the fixed portion of the wing is connected'to the latter by distortable members, the profile of which conforms to 00 that of the adjacent portions for avoiding any oifset portion and allowing to extend the movable surfaces out without preventing for a single moment the warping operations, the said members being for instance. constituted by casings made of rubber or equivalent material reinforced, if need be, by metal elements.

- '(i) For causing the thrust of the wind to intervene in order to limit the power necessary for extending out and folding the movable'surfaces, 1

the latter are provided, at .theirends, with fins so pivoted that the combined reactions of tension cables and of the movable surfaces themselves, set these fins in the windin-order that the latter should generate a component directed in, the direction of the stress to be exerted for extending .outorfolding the movable surfaces.

' (7) Thefinsaccordingto (i) aresodevised that, a in retracted position of the movable surfaces wound on their they close the openings' m formed in the wall of the fuselages, or hulls, containing these drums, so that the aerodynamic qualities of the entire airplane should be optimum when the latter flies with the reduced surface suitable for high speeds.

(k) The fins can also be so devised that, the movable surface being completely extended out, their angular displacements can be controlled by the pilot, the latter then utilizing them as auxiliary rudders oras compensating planes in case of stoppage of a side engine on a multi-engine airplane.

(l) Undercarriages, in the case of airplane, or floats at the ends of the wings, in the case of sea planes, are supported by the central portions of the end ribs of the movable surface .and are so devised that they canbe withdrawn within the fuselage or hullwhen the movable surfaces are wound on their drums.

The invention also extends to various detail points and forms of construction which will be indicated in the specification given hereinafter, with reference to the accompanying drawings which illustrate, by way of example only, various means and combinations of means suitable for carrying out the features set forth in the foregoing:

Fig. 1 is a side view of a rib of a movable surface, in position on a fixed surface.

Fig. 2 is a view corresponding to Fig. 1, with partial sections and parts broken away.

Fig.3 is a plan view corresponding to Fig. 1.

Figs. 4 and 5 illustrate the assemblage and .control of the ribs of the movable surfaces.

Fig. 6 is a sectional plan view of a fixed surface with a warping aileron and its control means. Fig. 'I is a side view corresponding to Fig. 6.

Fig. 8 is a partial elevation of a rib for a movable surface the curvature of which is variable during flight.

Figs. 9 to 11 are perspective views of airplanes and seaplanes provided with improvements acthe device for locking the movable portions of the ribs of the movable surface on the central portions of the same ribs.

. Fig. 20 is a partial plan view of an arrangement for bracing the ribs relatively to each other when the movable surface is extended out.

Fig. 21 is an elevation, on an enlarged scale, showing how a movable rib portion is pivoted on the central portion of the rib, the bracing device being illustrated in section.

Fig. 22 is a cross section made according to line BB of Fig.20.

Fig. 23 is a plan view showing the bracing vice in the region adjacent to the ribs.

The movable surfaces according to the invention are constituted by transverse ribs made of several elements, one of which, perfectly rigid,

and in the rear of the trailing edge.

Thus, in the'example of Figs. 1, 2 and 3, each rib is composed of two elements: a centralelement latter is preferably made of metal and is of the. longitudinal box type, with an external surface absolutely smooth. By means of the arrangement described, each rib element 1 is perfectly guided relatively to the plane 2 and can move along the latter in translation only in the direction of the span.

The leading element 3, pivoted on the element 1 about a stud 4, is transversely held by fitting in a fork piece 1 having a U-shaped cross section and provided at the end of the element 1. At its rear end, the leading element 3 is provided with a roller 8, through which it bears on the extrados surface of the fixed plane 2.

It is to be noted that if the central element 1 bears, in this example, on the intrados face of the plane 2, it is simply because the struts and bracing wires' connecting this plane to the fuselage or toother planes of the airplane are connected to the extrados face. It is obvious that the central element 1 must bear on that of the faces of the fixed plane 2 which is completely free from any external connection. Thus Figs. 4 and 5 show the element 1 as hearing on the extrados face of the fixed plane.

The ribs can be made entirely of metal, or partly of metal'and partly of wood; they are connected together by jointed links. In the example of Figs. 1 to 3, a first series of these links 9 constitutes the leading edge of the movable surface and two other series 10 and 11 constitute chains arranged on either side of the fixed plane 2, the seriesll forming the leading edge of the rear elementof the movable surface. The pivot pins of the links being arranged parallel to the direction of the ribs, the latter can wind on drums with theflexible covering which encases'them. This flexible covering can be provided only on the leading and trailing portions of the ribs, so as to constitute with the fixed plane, when the movable surface is extended out, a slotted wing.

The object of the joints such as 4, between the rib elements is'the following:

Each rib is devised for imparting to the movable surface, when extended out, an important curvature which gives it a very high lifting power. This curvature, owing to the joints 4, appears only if the ribs bear on the fixed plane 2. As soon as a rib, when the movable surface is being wound on its operating drum, ceases to be in contact with the fixed plane, .the jointed elements constituting it move. substantially in alignment with each other in order to limit to the minimum the cumbersomeness on the drum, and this whatever may be the number of jointed elements constituting the rib.

These elements can be four in number if it is desired to obtain an extended surface having a variable curvature during flight. Thus, as shown in Fig. 8, which illustrates the front portion of a trailing element of a rib, thelatter has'a central portion 1 which bears on the fixed plane 2, a leading portion pivoted at the front of the central in the form of a'hollow body of sheet metal, proa w a portion, as explained with reference to 1 and 2, and a tra ling P rtion 12 having its front end vided with two lugs by which it is loosely articulated to the shaft 13 carried by the central rib 1.

The lever 14 is also loosely articulated about the same shaft 13 and when the movable surface extended, the lever which carries a roller 15 on its front end, bears on the fixed-surface 2, The rear end of the lever is connected by a flexible link and a spring 1'1 to a point 16 of the trailing portion 12, the spring tending, in'the absence of any external cause, to keep thefaces- 14' and 12*.

against each other. An abutment 18 provided on the lever l4 is adapted to associate with a corresponding abutment 19 provided on the rear end of the central portion 1, when the movable surface is extended so as'to ensure a rigid connect ion-.between the central portion and the lever, 20

sov as to reduce the curvature of'the wing when the speed of theairplane increases beyond a predetermined value. If, at high speeds, it is desired to transform the wing presenting a high curvature and having a high lifting power intoa wing hava-double curvature and of smaller lifting power, it suffices to provideat the rear, ends of the portions 12 jointed elements connected by a nonextensible cable-21 running over the pulley to the end of the lever 14, so that, in the manner known per se, the displacement of each portion 12 position indicated by dot and dash lines in mission pulleys 'can be concealed withinthe bob:-

7 in the direction of the arrow acts, through the r medium of the cable 21,- for raising the end trail- 40 ing elements and the covering encasing them, above the adjacent plane corresponding to the portions 12. The entire wing then assumes a double lifting curvature, the center of thrust of which isv brought towards the fixed plane 2.

'It is obvious that when the rib 12 occupies the Figure 8 the small pulley over which the flexible link runs will be displaced relatively to the rear fixed end of the lever14 to such an extent that the spring 17 will be extended to nearly twice its initial'lengthc The reaction tends to bring the rib 12 in an 'inversedirection to the arrow, that is to say in antagonism to the pressure of the air on the flexible surface borne by the ribs 12.

The spring 1'7 and the cable 21 with its translow rib 12, as is already known for wings the ourvature of which is variable in flight.

When the movable surface is withdrawn by rotation of itsioperating drum in the suitable direction, as soon as the roller 15' ceases tobe in contact with the fixed plane 2, all the elements of Q the rib can place themselves according to thesame common theoreticaLaxis, for the purpose indicated above (as shown in dot and dash lines As in known wings the surface of which is va riable by displacement of movable surfaces in the direction ofthe span of the fixed planes, the free ends of the movable surfaces are connected to tension cables which wind on control drums.

-'When it i'sdesired to extend t-he' movab e surfaces out, it, is .thecables which act as-tractive elements; when'the movable surfaces are to be withdrawn, it is the drums on which the. latter wind which act as driving elements.

According to the invention (Figs. 4 and 5), the tractive cables pass in some of the longitudinal boxes of the fixed plane 2 and are suitably guided on pulleys 22, the pivots of which are supported by longitudinal walls of the boxes. The ends of the central portion 1 of the end rib of each movable surface are provided with securing means, such as a fork piece 23, to which thecorresponding cable is attached. The fork-pieces 23 I slide in a longitudinal groove or opening 24 of thecovering of the fixed plane 2. This opening can be closed, when the movable surface is withdrawn, that is to say,- when it is wound on its drum, by the cable itself which, in this case, is in the shape of a fiat ribbon, throughout its length or only on a portion of the latter .correspondopening of the fork embracing the leading edge of the fixed plane. v Fig. 15 diagrammaticallyillustrates the mech-- -anism controlling two movable surfaces each corresponding to a fixed plane. The movable surfaces with their ribs already described each wind on one of the drums 26 which are so conv trolled as to rotate in reverse direction;

The drums can be driven by an electric motor 27 which can be put in or out of circuit at the pilot's desire. Each of the ends of the shaft' of .this motor is provided with a coupling device automatically thrown in or outv of gear according to the direction of rotation of themotor: This coupling device can be of any construction as it .does not form a part of the invention. One of the couplings'28 can drive, through a pinion '29, a-

gear 30 fast on a shaft 31 rigid with-two worms 32 'and 33 permanently meshing with worm wheels 34 and B5 rigidly secured on the drums '26. The other coupling can drive a toothed wheel 36 loosely mounted on a bearing -portion of the shaft 31 and connected, by a set of gears 37-38. to a shaft 39 driving, through a worm 40, a worm wheel '41 rigidly secured on a drum 42 controlling cables 43 connected to the free ends of the movable surfaces, The drums 26 and 42 are permanently b'raked by any suitable device so as to constantly ensure the tension of the movable surfaces and. of their cables.

The motor 27 which is of the reversible type, isput in circuit for unwinding or winding up the two movable surfaces. .According to its direc-- tion of rotation, the motor drives: either the shaft 31 which simultaneously controls the drums of the two movable surfaces, the drum of the cable being then loose, butbraked for ensuring a suitable tension of the surfaces and cables.

The invention relates to'means causing the relative wind to intervene for facilitating the extension and retraction of the movable surfaces.

These means substantially consist in pivoting on the ribs of the movable surfaces, shutters which set or orientate relatively to the relative wind,

so that the'latter by the thrust it exerts on the said shutters, produces a component; directed in the direction of displacement of the movable surface.

' fuselages or hulls.

Figs. 12 to 14 diagrammatically illustrate a form of construction of the said means. The'two end ribs of a movable surface can be rigidly braced so as to constitute a supporting frame for aspindle 44 arranged at right angles to the planes of the ribs and on which a shutter 45 is pivoted.. {At a point 46 of this shutter is attached the end of one of the tension cables already mentioned. When one of the movable surfaces is to be extended out, the cable acts by exerting a pull in the direction of the arrow 49 and sets the shutter as shown in Fig. 13. The shutter45, held against an abutment 47 of the movable surface, inclines relatively to the relative wind (direction of the arrow 48), the thrust of which on the shutter creates a component directed in the same direction as the tractive stress. At the end of its displacement, the shutter abuts against an abutment 50 of the fixed plane which restoresit in the direction of the relative wind, as shown in Fig. 14.

When a movable surface is to be retracted,

another cable 51, connected to the drum for .winding up the movable surfaces, acts by exerthaving also a U-shaped cross section, as shown. The locking member is constituted by a yoke 57 arranged at the end of a lever 58 pivoted at 59 on the leading portion 3 and restored by a, spring 60. The action of the spring 60 is such that, in the absence of any external cause, the top of the yoke is moved upwardly, so that the ends 57 are entirely contained within the portion 3.

But, when the movable surface is extended out. a suitable surface or incline provided at the butt end of the fixed plane 2, comes in contact with a roller 61 arranged at the free end a of the lever 58 for moving the latter in antagonism with the reaction of the spring 60; the

face winds.

In the constructional modification illustrated in Figs. 18 and 19, the movable rib 3 is locked on the ing a pull in the direction of the arrow 52, and

sets the shutter as shown in Fig. 12; the component produced by the thrust or the relative wind is again directed in the direction of dis-' placement ofthe movable surface.

' One of the important features of the invention consists in utilizing shutters, such as 45, for

closing the openings provided in the fuselages or hulls for the passage of the movable surfaces, the drums of which are arranged within these plane presents all the aerodynamic qualities suitable for providing great fineness. An assembly similar to that of the shutters 45 on the movable ribs can be combined with frames or undercarriages which come in action only-upon flying oil and landing. Instead of undercarriages, and as shown in Figs. 10 and 11, floats 54 can be provided at the ends of the wings. in the case of seaplanes: these floats, when the seaplane is flying at high speed, are. withdrawn within suitable housings '55 of the hull (Fig. 11) and they eliminate the step prejudlcious to the aerodynamic qualities, but indispensable for the nautical qualities of the hull. The invention also. relates to means allowing to lock, on the central portion, the leading portions of the ribs of the movable surfaces, when the latter are extended out. A leading portion is thus obtained which, during flight, forms Ia rigid structure with the central portion. But, upon folding of the movable surfaces. when a rib ceases to be in contact with the fixed plane 2, the locking means cease to act for allowing the entire rib to rectify its curvature and to wind on the drum with the minimumcumbersomeness.

By way of example, these locking means can beconstructed as shown in Figs-18 and 17. The rear end of the leadingportion 3 of the rib is of U shape in cross section. It is pivoted,

central rib 1 by the following means: I .1 A dog 75 is pivotedat 76 on the movable rib 3 and carries a pin 77 on which a roller 78 is journalled. A yoke 79, connected to the end of the pin 77, is attached, through a link 80, to a fixed point or pin 81 of the central portion 1. A lever 82v is, on. the other hand, pivoted on the dog 75 and freely passes through the rib 3. The outer end of the lever 82 carries a roller 83 which comes in contact witha suitable incline provided at the butt end of the wing, and operates similarly to the roller 61 of Fig. 16. When the movable surface is extended out, the lever 82 is urged outwardly, and the dog 75 assumes the position shown in-Fig. 18, the three points 81, 84 and 76 being in a straight line and the dogabutting at 85. The

roller 78 (several of which can moreover be provided, two for instance) bears on the edge of the fixed plane 2, as the rollers 7 of Fig. 3.

When the movable surface is folded, upon the ribs reaching the butt end of the wing, thelever 82 is pushed back. and the elements of the mechanism assume the position shown in Fig. 19. Figs. 20 to 23 illustrate a device for bracing the movable ribs relatively to each other, when the movable surface is extended out. A cable 24", such as a steel wire and so-calle "piano string", which corresp'onds to 24 (Fig. 5) and participating in the unfolding and folding of the movable surface, passes through the fixed portions 1 of the ribs near the leading and trailing edges of the plane 2 and constitutes a pin or stud for-the two hinge eyes 86 and 87 of a hinge,

members 88. The ribbon 87 is made of sections the width of which corresponds to the distance able surface is extended out. Each of these sections leads at its ends to the corresponding ends of the hinge eye 87, which ends are provided with angle members 89 in which is provided a curved slot 90 for allowing the passage of a finger 91 secured on the movable portion 3 of the rib.

Referring to Fig. 21, itwill be seen that; when the movable surface is extended outrthe ribbons 87 are. raised at right-angles tov the, ribbons 86',

' fee ableportions 3-of the ribs, by pivoting-about the pins 56 in order to straighten, move the ribbons 87 down in the position shown in Figs, and 22 for constituting aflexibl unit '86 24'87'which does not prevent the movable surface from winding up on its operating drumsr I On the hinge eye 86, wooden or like reinforcing members 92 can be provided for reinforcing and holding the edge of the flexible wall secured on the movable portions 3 of the ribs and which constitutes the covering of the movable surface. As'is already known, when the movable surfaces are extended out, their ends can be warped for ensuring transverse balance of the airplane. 20 According to the invention, the warping of the movable surfaces is obtained by the following means: Each fixed plane 2 is provided at its end with a warping aileron 2 which forms an extension of (Figs. 6 and '7)'.is of the longitudinal metal box ty'pe-andis journalled in bearings 8.4 carried by a spindle 63 secured on the fixed plane 2; These bearings support sheet metal plates 65 riveted oi welded on'braclrets 66 rigidly secured on the inner longitudinal faces of the a'ileron.- This assemblage, owing to the interposition of slightly warpable sheet metal plates 65, renders the operation 'of theaileron easy, notwithstandingrthe distor- 'relatively. to the shaft 63' are obtained byoperat- ;ing cables or chains arranged within the fixed plane and acting on' a grooved pulley or on apin- -io'n suchasfi'lmountedonashaftiissecuredbya collar 69 on the shaft 63. .A bevel pinion '70, rigid with the pinion or pulley B'LIactuates the aileron 2% through the medium of abevel pinion '71. Y

The extension of the movable surface along the fixed plane 2 should be eifected up to the end. of the aileron; without preventing for a single moment to effect the operations necessary for preserving the transverse balance of the airplane,

For that purpose, the adjacent tr faces of the aileron 2* and of the'fixed plane 2 are, accord- .ing to an important featureofthe invention, cut away for providing between them .a space for receiving boxes. 72 having distortable "walls and made of rubber or equivalent material. These boxes [2 which, inthe example illustrated, have, in plan view, the shape of wedges with their apices opposed to each other, are 'so shaped as to exactly,

- join the aileronto the fix'ed'plane. Theyare suitably secured to the transverse faces ofthese two latter elements. and can, if n, be 'rein- I forced by metal parts such as a sheet metal member 73 facilitating the zregular distribution of the distortion stresses when the aileron is operated. By means .of this arrangement. whatever may be the angularposition of the aileron, thecentral course of extension, do not encounter gaps caps.-

ble of preventing their displacement along thefixed plane. .The end ribs of the fixed surface, owing to-the pla'y'provided in 'the'joints of the chains connecting them-canmove with the aileron and thisQas well when the surface is completely extended out as whenv the said. surface is being extended out. 7

What I clai'mas my invention anddesire to sethe fixed portion of the plane. This aileron.

' tions of thelatter; Its angular. displacements theelements with the fixed wings.

portions of the ribs of the movable surface, -in-- I -wing,said second element pivoted on the leading 1. In an airplane, a variable lifting surf comprising fixed wings, flexible walls movable along the fixed wings, transverse ribs in the flexible walls, operating drums on which thewalls and ribs are wound, said ribs being composed of articulated elements and means associated therewith for causing relative displacement of the articulated elements and cooperating with the elements to form either a unit with great-curvature when bearing .on the fixed wing or a unit with no curvature when the said unit leaves the fixed win .to'pass on to the operating drums. V

2. Inan airplane, a variable lifting surface comprising fixed wings, flexible walls movable along the fixed wings, transverse ribs in the-flexible walls, operating drums on which the walls and ribs are wound, said ribs constituting a unit composed of a first element and a second element, said first element movable on one of the faces of a fixed wing and extending beyond the leading and trailing edges of said. wing, means associated with both elements-for causing relative displacementthereof including rollers onthe first element for guidingthe latter along an adjacent fixed wing, said second element pivoted on the leading edge of the first element and the trailing edgeof the second element bearing on the fixed wing so that the rib unitmay have a great curvature when it .is on the fixed wing and no curvature .whe'n'it passes. over an operating drum.

' 3.--In an airplane as claimed in claim 2 wherein the means for causing relative displacement also includes a mechanism for effectingan initial displacementimmediately prior to engagement of 4. In an airplane, a variable surface comprising fixed wings, flexible walls movable along the fixed wings, transverse ribs in the flexible walls, operating drums on 'which the walls and ribs are wound, said ribs constituting a unit composed of a first element and 'a second element, said first element movable on one of the faces of a fixed, wing and extending beyond the lead- 'ing and trailing edges of said wing, means associated with both elements'for causing relative displacement tmreof including rollers on the first element for the latter'along an adjacent fixed wing, said second element pivoted on the leading edge of the first element and the trailing edge of the second element bearing on the fixed wing, means for locking the said second element to the firstelement when the elements bear on thefixedwing. 1

5. In an airplane, a variable lifting comprising fixed wings, flexible walls movable along the fixed wings. transverse ribs in the flexible walls, operating drums on which the walls and ribs are wound, said ribs constituting a unit 1 composed of a; first element and a second element, said -firsteleinent movable on one of the faces of a'fixed wing and extending beyond the leading and trailing edges of said' wing, means associatedwith both elements for causing relative displacement thereof including rollers on the first element for guiding the latter along an adjacent fixed edge of the firstelementsand the trailing edge of the second element on the fixed wing, said means also including a member pivoted to the second element, a rodconnected to the said memher and projecting externally of the element,

the-rib unit is on manna wingand' for bringing thesaid member in unlocking position when the rib is' on the operating drum.

6. In an airplane as claimed in claim 1 wherein continuous flexible ribbons are provided for connecting'the said ribs, a flexible blade element between two consecutive ribs and articulated to the said continuous ribbons, means for connecting said element to one of the articulated ele-' ments of the rib so that the continuous ribbons and the blade elements are disposed in the same plane when the rib unit has no curvature and are disposed in two perpendicular planes when the curvature is maximum.

7. In an airplane; a variable lifting surface and trailing edges of the first element and bearing by their adjacent ends on one of the faces of the same fixed wing, and means for locking the second and third elements to the first element when the latter is engaged on the fixed wing.

8. In an airplane, a variable lifting surface comprising a fixed hollow wing, flexible walls movable along the fixed wing. transverse ribs in the flexible walls, operating drums on which the 'walls and ribs are wound, an aileron movable at its free end having the same width as the said wing along which it extends, an for the movable aileron disposed in the longitudinal direction of the wing and in the interior thereof, means for angularly displacing the aileron about the said axis, distortable means interposed between the adjacent ends of the aileron and the wings so that the displacements of the aileron do not produce a discontinuity between itself and the said wing. saidribs comprising two elements one of which is guided along the said wing and projects over the leading and trailing edges thereof while the other element is articulated to one of the ends of the guided element and supported by one end on one of the faces of the wing. and means for relatively locking the rib elements when the said rib is engaged on the wing.

9. In an airplane as claimed in claim'l, a fuselage, a fin fixed to the end rib of the flexible wall, a pivoting axis for the said fin and fixed to said end rib, means for turning the said fin' into the wind relatively to the airplane so as to utilize the same forfacilitating the unfolding and folding of the flexible surface, the said fln being adapted. to close, while the flexible wall is wound on its drum, the fuselage having an opening through which opening the said wall passes when leaving its operating drum to engage with the fixed wing.

10. In a hydroplane' as claimed in claim 1, a

fuselage containing the operating drums, flexible walls, floats mounted in the said fuselage and secured to the end ribs of the flexible walls movable along the fixed wings so that when the flex- J ACQUEB GERIN. 

